64 



R. R. BENSLEY 



15, in which weight was gained, and by cases 21 and 22, in the 

 next table, in which hkewise weight was gained during the ex- 

 periments, but in which, nevertheless, the thyroid gland remained 

 small. 



Table 5 represents the results of a series of experiments under- 

 taken with a view of determining whether any particular element 

 in the dietary was the cause of the hyperplasia. In this series, 

 number 19 received twice, number 20 two and a half times, num- 

 ber 21 three times, number 22 four times, and number 23 five 

 times the amount of meat indicated in the dietary for table 4. 

 Number 20 refused bread one day of the twenty-one days that 

 the feeding lasted, number 23 refused it four days. In all other 

 cases the full ration provided was eaten. 



In four out of the five cases in this series the results as regards 

 the size of the gland and the presence of mitoses were similar to 

 those of table 4. In the fifth case, namely number 23, the ani- 

 mal which received the largest meat ration, the hyperplasia was 

 of very high degree. Numbers 19 and 20 of this series were re- 

 markable for the high content of secretion antecedent in the cells 

 themselves. In 19 this substance filled the basal half of the cell. 

 Numbers 21 and 22 had a smaller store of intracellular secretion 

 but a relatively high content of intrafollicular colloid. Whether 

 these differences were the result of the experimental conditions 

 or mere accidental differences in the animals could not be deter- 

 mined from this one series, and the animals to repeat the experi- 

 ment were unfortunately^ not available. The result in number 23 



